Hugo Theorell—Nobel Prize for Study of Enzymes

Abstract

The 1955 Nobel Prize for medicine or physiology was awarded to Swedish physician-biochemist Axel Hugo Teodor Theorell for his work on the nature and mode of action of oxidative enzymes. His research on the structure and activities of the enzymes that facilitate oxidation and reduction reactions in certain cells advanced the scientific understanding not only of how cells use oxygen but also of how enzymes function in all their interactions. Theorell was the first scientist to produce a crystalline form of myoglobin (1932), an oxygen-carrying protein found in muscle, and to prove that myoglobin and hemoglobin were different. He also was the first scientist to isolate a coenzyme and the first to divide an enzyme into its constituent parts (apoenzyme and coenzyme). The second of three children, Theorell was born on Jul. 6, 1903, in Linköping, Sweden, a small town about 120 miles southwest of Stockholm; his father was a military physician, and his mother was a talented musician. At the age of 3 years, he was stricken with poliomyelitis, which left him partially disabled but ambulatory. He attended the junior school and state secondary school in Linköping. Theorell had planned to become a civil engineer, and in the summer of 1920, he was apprenticed to an engineer in the Swedish Railways. After graduating from secondary school in 1921, however, he changed his mind and decided to become a physician. Theorell entered Karolinska Institute in Stockholm in 1921 and received his bachelor's degree in medicine in the spring of 1924. That summer, he studied bacteriology at the Pasteur Institute in Paris. He returned to Stockholm in the fall and was appointed an assistant in the Medical Chemistry Institute at the Karolinska Institute. He continued his postgraduate studies and received his M.D. degree in 1930. From 1930 to 1936, Theorell was an assistant professor of biochemistry at the University of Uppsala (Sweden) and worked on ultracentrifugation with the Swedish chemist TheodorSvedberg(1884–1971). From 1933to 1935, hewas a Rockefeller Foundation Fellow at the Institute for Cell Physiology of the Kaiser Wilhelm Institute in Berlin, where he worked with the famous German biochemist Otto Warburg (1883–1970) on the isolation of a pure sample of “yellow enzyme” from yeast. In 1935, Theorell found that “yellow enzyme” consisted of two parts: an enzyme of vitamin B2 plus a phosphate group and a protein called apoenzyme (pure protein). “Yellow enzyme,” now known as flavin mononucleotide, was the first enzyme to be clearly defined and demonstrated another connection between vitamins and coenzymes. In 1937, Theorell became director of the Biochemical Department of the Nobel Medical Institute in Stockholm, where he remained until 1970. There, he studied the oxidative enzyme cytochrome c and determined the precise nature of the link between the iron-bearing, nonprotein porphyrin portion and the apoenzyme. Working with Britton Chance (1913) from the University of Pennsylvania in the late 1940s, Theorell turned his attention to another set of oxidative enzymes, the alcohol dehydrogenases. Because Chance and Theorell clarified the steps in the oxidation of alcohol to aldehyde in liver cells, the kinetics of this series of reactions is called the TheorellChance mechanism. Their research led to the development of blood tests for alcohol levels. During the 1960s and 1970s, Theorell served as administrator of the Wenner-Gren Society and the Wenner-Gren Foundation in Stockholm. He retired in 1970. He had a stroke in 1974, and his health began to deteriorate. After visiting the island of Ljustero, off the coast of Sweden, during the summer of 1982, Theorell died in Stockholm on Aug. 15,1982, at the age of 79 years. Besides the Nobel Prize, he was awarded many honors, including honorary doctorates from numerous universities around the world. In 1996, Theorell's native Sweden issued a stamp in his honor.